一种轴向离心风机CFD数值模拟及优化研究

发布时间：2018-05-11 17:41

本文选题：轴向离心风机 + 效率　；参考：《西南交通大学》2011年硕士论文

【摘要】：轴向离心风机是依靠输入的机械能,提高气体压力并排送气体的机械,它是一种从动的流体机械,广泛应用于工厂、矿井、隧道、冷却塔、车辆、船舶和建筑物的排尘和冷却,轴向离心风机的性能可用风机出口处的总压和风机的效率来衡量。以往对离心风机的研究主要采用理论分析和实验相结合的方法,而近几年来,CFD(Computational Flud Dynamics)技术的发展以及商用CFD软件的普及,使得通过计算机数值模拟和流体可视化的方法来研究轴向离心风机的内部流场和性能成为可能。本文利用ANSYS CFX10.0软件对THTF4.5轴向离心风机在设计转速工作状态下的特性进行了全三维定常数值模拟。论文主要内容包括以下几个方面：(1)用三维造型软件UG建立轴向离心风机内流场的几何模型,使用前处理软件ICEM CFD对风机流场划分结构化六面体H型网格,以保证CFD计算结构的高精度；(2)采用K-epsilon两方程紊流模型和RRF(Rotating Reference Frame)旋转坐标系模型,对风机整个内部流场进行求解。利用CFD稳态计算结果,分别对离心叶轮流场、静子流域子午面流场、支板流场和回流间隙流场进行后处理分析和研究。得出叶轮根、中流面的流场存在气流分离现象,并根据计算结果指出这种明显的不均匀气流分离现象是由于结构设计的不合理所引起；(3)以原始结构风机为基础,分别从优化支板结构和加装环形隔板的角度出发,提出两种优化结构,然后在流场分析和以往工程经验的基础上进行了两个优化方案的数值模拟计算,用以提高风机的出口总压和风机效率。CFD计算结果表明,两种优化方案的结果均好于原始设计,其中改进方案二的对性能和流场的改进幅度较改进方案一更大。通过和试验数据的比较,该离心风机的数值模拟结果比较令人满意,其流量、压比、效率等重要参数和试验相差在3%以内,两个优化方案的数值模拟结果明显好于原设计方案的数值模拟结果。
[Abstract]:Axial centrifugal fan is a kind of driven fluid machinery which is widely used in factories, mines, tunnels, cooling towers, vehicles, ships and buildings for dust removal and cooling. The performance of axial centrifugal fan can be measured by the total pressure at the outlet of the fan and the efficiency of the fan. In the past, the research of centrifugal fan mainly adopted the method of combining theory analysis with experiment, but in recent years, the development of CFDF Flud dynamic technology and the popularization of commercial CFD software, It is possible to study the internal flow field and performance of axial centrifugal fan by computer numerical simulation and fluid visualization. In this paper, the full-3D steady numerical simulation of the characteristics of THTF4.5 axial centrifugal fan under the working state of design speed is carried out by using ANSYS CFX10.0 software. The main contents of this paper are as follows: (1) the geometry model of flow field in axial centrifugal fan is established by using UG, and the flow field is divided into hexahedron H mesh by pre-processing software ICEM CFD. In order to guarantee the high accuracy of CFD calculation structure, the K-epsilon two-equation turbulence model and the RRF(Rotating Reference frame rotating coordinate system model are used to solve the flow field in the whole fan. The flow field of centrifugal impeller, meridional surface, branch plate and reflux gap were analyzed and studied by CFD steady state calculation. It is concluded that the flow field of the impeller root and the middle flow surface has the phenomenon of air flow separation, and according to the calculation results, it is pointed out that this obvious phenomenon of non-uniform air flow separation is caused by the unreasonable design of the structure) and is based on the original structure fan. From the point of view of optimizing the supporting plate structure and installing the annular diaphragm, two kinds of optimization structures are put forward, and the numerical simulation of the two optimization schemes is carried out on the basis of the flow field analysis and the previous engineering experience. The results show that the results of the two optimization schemes are better than those of the original design, and the performance and flow field of the improved scheme 2 are larger than that of the first one. By comparing with the experimental data, the numerical simulation results of the centrifugal fan are satisfactory, and the difference between the important parameters such as flow rate, pressure ratio, efficiency and test is less than 3%. The numerical simulation results of the two optimization schemes are obviously better than those of the original design scheme.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH432

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